The present invention relates to an electro-magnetic clutch control system, and more particularly to an electro-magnetic control system which is capable of diminishing the shock to the car body caused by the shifting gears in the transmission, as well as of minimizing the slipping of the electro-magnetic clutch during acceleration of the car.
The electro-magnetic clutch comprises an annular drive member secured to the crankshaft of an engine, a magnetizing coil provided in the drive member, a driven member secured to an input shaft of transmission spaced, leaving a small gap from the drive member, and a shift level for the shifting or changing of the gears in the transmission. The shift lever is provided with a switch for the magnetizing coil, which is actuated by operating the shift lever. When the shift lever is shifted to the gear engaging position, the switch is closed so that electric current flows through the magnetizing coil to magnetize the drive member. As the accelerator pedal is depressed, the current applied to the coil increases. The magnetic flux is aggregated in the gap between the drive member and the driven member, so that the driven member is coupled to the drive member. The clutch current passing through the magnetizing coil progressively increases according to the degree of depression of the accelerator pedal, while the clutch slips between the driven member and the driven member. Thus, the car may be smoothly and easily started by depressing the accelerator pedal without operating the clutch pedal. This is a well known technique.
However, in such a conventional electro-magnetic clutch, the driver of the car often gets an unpleasant shock sensation, if the clutch is immediately coupled after changing gears of the transmission. In a conventional control system, during a predetermined time after the completion of the gear-change, electric current smaller than a rated current is supplied to the coil of the clutch to put it in a partial engagement condition, that is the slipping condition. After the predetermined time, the clutch is completely connected, so that the shock of the connection of the clutch may be decreased. However, the clutch current and the control period for the partial-engagement condition are fixed to predetermined values. However, with a long slipping period due to the partial engagement during acceleration, especially during rapid acceleration, the driving feeling would not be so good. On the other hand, with a short slipping period during deceleration, a great shock would occur to the car body.